drop the grafana in ns monitoring

It reads from `prometheus.monitoring.svc:9090`, which does not exist on this
cluster -- so the panel has been a second lens onto nothing. Zoo's telemetry
goes to o11y over OTLZ, and one lens is the point.

It also carried `GF_SECURITY_ADMIN_PASSWORD: admin` beside
`GF_AUTH_ANONYMOUS_ENABLED: true`, in the clear, in a file in the repo. No
ingress pointed at it, so the exposure was in-cluster only, but "no route today"
is not a control.

Its 256Mi is what the otel-agent rollout on zoo-nodes-3mm2zq has been waiting
for: that node is at 99% of allocatable, the agent asks 192Mi, and a DaemonSet
rolling update stalls the whole set on one unschedulable pod.

deploy/monitoring/grafana.yaml

@@ -1,41 +0,0 @@
-# Generated from the live monitoring/grafana Deployment on do-sfo3-zoo-k8s
-# by hack/live2values.py. Live is the source: a repo of hand-applied
-# manifests has unknown currency, the running fleet does not.
-replicas: 1
-selectorLabels:
-  app: grafana
-image:
-  repository: grafana/grafana
-  tag: 11.6.0
-  pullPolicy: IfNotPresent
-env:
-- name: GF_SECURITY_ADMIN_PASSWORD
-  value: admin
-- name: GF_AUTH_ANONYMOUS_ENABLED
-  value: 'true'
-resources:
-  limits:
-    memory: 1Gi
-  requests:
-    memory: 256Mi
-volumeMounts:
-- mountPath: /etc/grafana/provisioning/datasources
-  name: datasources
-- mountPath: /var/lib/grafana
-  name: data
-ports:
-- containerPort: 3000
-volumes:
-- configMap:
-    name: grafana-datasources
-  name: datasources
-- name: data
-rollingUpdate:
-  maxSurge: 25%
-  maxUnavailable: 25%
-topologySpread:
-  enabled: false
-lifecycle: null
-terminationGracePeriodSeconds: 30
-defaultReadinessProbe: false
-imagePullSecrets: []